Get rid of all the library tags.

lib/src/sdk.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// Operations relative to the user's installed Dart SDK.
-library pub.sdk;
-
 import 'dart:io';
 
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 
 import 'io.dart';
 
 /// The path to the root directory of the SDK.
 ///
 /// Note that if pub is running from source within the Dart repo (for example
@@ skipping 49 matching lines @@
   var version = "$major.$minor.$patch";
   if (channel == "be") {
     // TODO(rnystrom): tools/utils.py includes the svn commit here. Should we?
     version += "-edge";
   } else if (channel == "dev") {
     version += "-dev.$prerelease.$prereleasePatch";
   }
 
   return new Version.parse(version);
 }